I was at my fave wrecker's in The City last week and found these three rods. I didn't hesitate and aquired all three for next to nothing. The yellow duece roadster has a blown 392 Hemi. The blue Model T RPU has a 4 pot Nailhead and check out the beer keg fuel tank! The red rear engine digger reminds of Tony Nancy's beautiful dragster.
Not sure how long they made these, but you could buy them new at least as late as 1980 or so - I played with them, about that time, and they were bought new for me.
I think you could get these at the 5&10 stores. They had them in bins and sold for 25 cents or 49 cents. These are TootsieToys.